Method of making weldless chains



J. F. CRAVEN.

METHOD OF MAKING WELDLESS CHAINS.

APPLSCAHON man APR. 3, 19m

WITNESSES NVENTOR all unirnn stares PATENT OFFIQH' METHOD GE MAKING: W'ELDLESS CHAINS.

LS SSJZZ.

Application filed April 3 To all whom it may concern:

Be it known that 1, James F. Craven, a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Making VVeldless Chains, of which the following is a specification.

This invention relates toa method of making solid link chains, by forging directly from bar, without any welding operation. The. object of the invention is to provide a method 01 making chains of the character described whereby the metal bar is formed directly into a chain of weldless links without the loss or removal of any metal, and whereby all of the operations can be effected by means of strong, simple, and durable tools cutting transversely to the axis of the bar, and upon successive links, so that in etl'ect a solid bar is fed in at one end of the machine and taken out in the form of a finished chain, embodying all of the metal originally in the bar. at the other end. thereof. A. further object is to provide a method of making chains directly from rectangular bars, without the necessity of first specially shaping the bar. Another is to provide a method which permits the use of bars of different areas in cross section, while producing therefrom chains of a standard size.

The invention comprises the several method steps hereinafter described. In the accompanying drawing, Figure 1 shows at the left a rectangular bar,-an ordinary standard billet-bar, no special rolling being necessary,and at the right a finished chain link, and between the two ends the succes sive steps in thetransformation of the bar into a chain; Fig. 2 is a longitudinal vertical section showing a set oi dies illustrating their action on the metal bar to roughly forge a chain link; F 8 shows a partial horizontal section and plan view oi the lower die member of Fig. 2, on the line 8-3 thereof; Fig. is a partial vertical section and elevation of a set or" dies used for piercing the roughly formed links; Fig. 5 is a horizontal section on the line 5-5 of Fig. l; Fig. 6 is a view of a pair of dies used to sever the finished linkand 7 is a partial section and plan view of the dies in Fig. 6 in operative position, preliminary to the severing operation.

The bar from which the chain is made is preferably square lIl-ClOSS section, although Specification of Letters Patent.

Patented Feb. 8, 1921.

Serial No. 223,400.

some variation from this form may be allowed. The operation of transforming it into a finished chain is a forging'process,

all the steps of which are performed with the metal at a good forging temperature. The bar 1 is fed into the machine end first, and is acted upon successively by the dies shown in Figs. 2, l, and 7, forming in reverse order the chain links A, B, C, D, E, F, G, H 1, etc. All of these dies act in a direction perpendicular to the axis of the bar, and are driven by presses designed to exert the required pressure, as will be clearly understood.

The first set of dies comprises two 0ppositely disposed similarly formed die members 2-2. adapted to be moved toward each other. These dies are formed with lateral supporting pins 8., and have recesses 4; adapted to form positive link portions l, and projections 6 adapted to press out metal between the link portions i to form r cesses 6, bounded by the linl: portions 4, as shown in Fig. 1. This set of dies forms the rough links, as shown at the left in Fig. 1. That is, the recesses 4 in the dies are pressed full or" metal, forming the portions 4 of the rough link, and the projections 6 of the dies press out the metal between the portions 4: ot the link, to leave recesses 6, on opposite sides of the rough link, and connected only by a thin web of metal. pressed almost entirely through at its middle point. After each operation 01" this first set of dies, the bar is rotated and moved forward a given distance, so that at the next opera tion of the dies, the rough link which has been partially formed in connection with the completion of the preliminary forming operation of link A, (Fig. 1) is completed, and a portion of a succeeding link formed.

The rough links C are next operated upon by the two dies shown in Fig. 4. These consist of an upper male die member 7, comprising a flat base 8, having a link forming groove 9 therein, and a central piercing plunger 10, with a tapering point 11 and an untapered base portion 12 attached to the die faces, shaped in cross section as shown inFig. 5. Grooves 13 in the side of the plunger portion of the die 7 are adapted to fit over the links lying in the vertical plane. ,T he point 11 is adapted to puncture the web between recesses 6 at its middle point, where it is thinnest, and as the point passes downward through this web the rough link portions 9 are pressed outward and formed by pressure of the die walls into the elliptical link, E. The upright links are positioned in the grooves 13, which extend up into the base 7 or the die, and cotiperating slots let, in the lower die member 15. An annular groove 16, cooperating with the groove 9, above described, is provided in the face of the lower die member 15, and these grooves act to.

compress and smooth the surface of the link as it is expanded to final size.

After the links have been expanded and pressed into final shape by the dies of Fig. 4, thev must be separated from each other. F or this purpose a set of dies as shown in Fig. 7 is provided. These consist of tour cotiperating cutting dies, working in two pairs, one of which is shown in Fig. 6. These comprise bases 19, from which extend lateral cutting portions 20, which are of suchsize that they can be positioned inside the unsevered link, G. Each of the cutting extensions is adapted to form one-halt oi a curved cutting tool suitable for severing the links F and H from link G. That is, when a pair of cutting dies is extended into the pierced portions of the link G, from opposite sides of the link, the cutting edges meet in the central plane of the link and form in etlect a single curved cuting tool adapted to fit around the inner portion of the link G, and to bear against the junction of that link with links F and H, at opposite sides oi. the cutter. Two pairs of cooperating half cutters are used, making in effect two cutters, and when these have been properly positioned inside the link by insertion from each side of one-hall ofeach cutter, and clamped together, pressure is then applied to bring the two positioned complete cut ers together to sever both sides of link G. This final'movement which is at right angles to the preliminary or inserting movement cuts the connection between the links F, G, and H, and completely frees the link G. The cutting movementis perpendicular to the axis of the bar and is parallel to that of the first two sets of dies.

T his'method of inserting the cutting tools laterally within the link, and then bringing together by pressure at right angles to the axis of the bar, permits the use of a double cutting tool. That is, two cuts may be made with the same stroke oi the tools, completely severing two links. ,Consequently, the cutting operation is performed one half as often as has heretofore been the custom. This allows the cutters to cool and permits a stronger construction, as the cutting edges are balanced, and pressure is applied directly behind the edge.

After this operation the bar is rotated and moved forward until the next parallel link to the one just severed is in the same 5 bar.

position as was the severedlink, and the cutting operation repeated. It should be noted that the operation of these dies is completely a cutting action, and does not shear the metal as is the case with tools heretofore used for severing links. The shape of these cutters, and the pressure under which they are operated, result in rounding the inner surfaces of the links at the severed portions so that no further smoothing action is necessary.

Referring to the first set of dies, which press the metal out into a rough link, it will be noted that the pins 3 are so positioned as to laterally bound the link being roughiy former. These bounding elements result in forcing the metal to flow longitudinally to the ends of the rough links, and therefore to secure a symmetrical thickness therein. l i ithout these bounding pins the tendency would be for too much metal to be forced out into thesides of the rough link rather than into the ends thereof. This has to be controlled, otherwise the piercing operation would not prodce symmetrical link, but wouldv form one much thicker on the sides than at the portions nearest the connection to the adjoining link. pins the excess of metal at the sides of the rough link is controlled. The portion of the link bounded by the pins becomes the end of the finished elliptical link, and an excess of metal this point is desirable, as that is the point of wear in use. The pres ent method secures this reinforcing oi' the link at its finished ends. It is an important feature of the method.

it will also be noted that by the method herein described, chains of standard size may be made from different sized bars. This, because the rough link forming is done by a set of dies in which the metal is pressed on all sides and practically forged in a fiXCl-CllII1811SlOI1Cl cavity. Therefore, when a larger bar isused, it is fed for a less distance at each link forming step, than where a smaller bar is used. In other words. the process is one of forging metal out into proper sizes and shapes for a link of a given size and thickness, and the length of bar used for forming each link dependsupon the volume of the metal in the When the size of the bar varies the metal ted in for each stamping is varied to secure the required amount for a single link. By this method a bar of a given length may be formed into a chain of a considerably greater length.

Other uses and advantages of the invention will be apparent to those familiar. with By properly positioning these,

Without removing any of the metal, then piercing the links and expanding them to approximately final size and form without removing any of the metal, and then severing the links from each other by true cutting tools first inserted in the periphery of a link by movement in one plane, and then forced together in a plane perpendicular to the first plane to cut the connecting Web, Without removal of any metal.

2. The process of making welnless chains which consists in stamping rough links from a bar Without the removal of any metal, then piercing and expanding the rough links to final size Without removal of any metal, then severing the links from each other, said forming, piercing, and severing being performed upon successive link portions by lateral pressure in the same plane.

3. T he method of making Weldless chains comprising the steps of stamping out the end of a metal bar to approximately the shape of a chain link without removal of any metal, then piercing the metal inclosed by said link and opening it out into rounded form, then severing the link from the bar, said pressing, piercing, and severing being successively performed by means of lateral pressure in the same plane and perpendicular to the axis of the bar.

l. T he method of making vveldless chains consisting in indenting the end of a metal bar to form link-shaped portions therein, piercing out the interior of said link-shaped portions, and cutting the links from each ther by means of dies moving perpendicular to the axis of the bar and inside the periphery of the link being severed.

5. The method of making weldless chains comprising the steps of pressing out the end of a metal bar into rough shaped links,

piercing the metal inside said links to press it laterally into the link itself, and severing the links from each other by tools operating perpendicular to the axis of the bar Within the periphery of the link being severed, the metal during the first pressing step being trapped so as to give a controlled distribution of metal in the finished link.

6. The method of making weldless chains comprising the steps of pressing rough linkshaped portions in the end of a metal bar, said portions comprising an outer Wall and an inner Web, the metal being restrained during the pressing operation so as to form the outer link Wall of substantially uniform cross section, then piercing the metal inside the rough link Walls and forming the rough link into a finished size by the piercing operation, then severing the finished links from each other by cutting perpen dicular to the axis of the bar and parallel to the central plane of the link being severed.

7. The method or making Weldless chains comprising the steps of forging rough links from a bar, pressing the links to finished shapes, and. severing the links from each other two at a time by cutters positioned inside the periphery of a link and moving perpendicular to the axis of the bar.

8. The method of making Weldless chains comprising the steps of forging rough links from a bar, pressing the links to form with an excess of metal on the outside, at opposite points of the links, and severing the links from each other two at a time by cutters moving inside the periphery of a link and parallel to the central plane thereof.

In testimony whereof, I have hereunto set my hand.

JAMES F. CRAVEN.

/Vitness GLENN H. Lnansonn. 

